1. Field of the Invention
The present invention relates to an optical scanning-type touch panel which inputs information thereinto by touching a plane such as a display screen of a computer which is specified as a section to be touched by means of an indicator.
2. Description of the Prior Art
In the case where information displayed on a screen of a personal computer or the like is inputted by a touching method, it is necessary to detect a touched position (indicated position) on the display screen accurately. As a method of detecting the indicated position on a display screen, xe2x80x9cCarol methodxe2x80x9d (U.S. Pat. No. 4,267,443) is known. According to this method, an optical matrix is structured on a front surface of a display screen by arranging light emitting elements and light receiving elements oppositely in a frame on the front surface of the display screen, and a position where a light is cut off by touch of a finger or pen is detected. According to this method, a high S/N ratio is obtained, so the method can be applied to a large-sized display apparatus, but since resolution of detection is in proportion to arrangement intervals between the light emitting elements and light receiving elements, it is necessary for high resolution of detection to reduce the arrangement intervals. Therefore, in order to detect a touched position accurately even in the case where a large-sized screen is touched by a thin material such as a point of a pen, there arises a problem that a number of light emitting elements and light receiving elements to be arranged is increased and, thus, the arrangement becomes large, and signal processing becomes complicated.
In addition, another optical position detecting method is disclosed in Japanese Patent Application Laid-Open No. 57-211637/1982. According to this method, a focused light such as a laser beam is scanned angularly from the outside of a display screen, an angle where a special pen exists is obtained from two timings of reflected lights from the special pen having a reflector, and the obtained angle is applied to the triangulation principle so that a coordinate of the position is detected by calculation. This method can reduce a number of parts greatly, and can provides high resolution. However, there is a problem of operability such that a special reflection pen should be used, and the position of a finger, an arbitrary pen, etc., cannot be detected.
Still another optical position detecting method is suggested in Japanese Patent Application Laid-Open No. 62-5428/1987. According to this method, an light retro-reflector is arranged in frames on both sides of a display screen, a return light from the light retro-reflector of a light beam scanned angularly is detected, an angle where a finger or pen exists is obtained from timing that the light beam is cut off by the finger or pen, and a coordinate of the position is detected according to the triangulation principle to which the obtained angle is applied. In this method, detecting accuracy can be maintained with a small number of parts, and the position of a finger, arbitrary pen, etc., can be detected.
However, in the method disclosed in Japanese Patent Application Laid-Open No. 62-5428/1987, the detected touched position is occasionally deviated from an actually touched position due to an influence of a size or position of the indicator. Moreover, in the case where a finger-touched position is detected, when the screen is touched by parts of the hand other than this finger or an elbow touches, there arises a problem that a position which is touched by the parts of the hand other than the finger or an elbow is detected falsely and the position of the finger cannot be specified.
In addition, in the conventional methods, a light emitting element which emits a scanning light is frequently arranged so that an optic axis of the light emitted by the light emitting element is parallel with a scanning surface, and a light receiving element which receives a reflected scanning light is frequently arranged so that a direction of the received light is parallel with the scanning surface. For this reason, the light send/receive member becomes comparatively large, and this frequently disturbs the miniaturization of the whole apparatus.
Further, the display screen is generally rectangular and a scanning region is designed according to the display screen, and in this case when the arrangement is such that a light emitting element, light receiving element, light scanning element, etc., are arranged parallel with each other at the edge sides of the display screen so that the apparatus can be miniaturized. However, in the case of this arrangement, there arises a problem that a scanning light by the light scanning element is blocked by the light emitting element, light receiving element, etc., and thus a sufficient scanning angle cannot be obtained.
In the conventional methods, an off-set voltage is changed because of an influence of sensitivity caused by a change in temperature, etc., of the light receiving element, and thus there is a possibility that accurate measurement cannot be made.
In addition, in the conventional methods, the time required for the light receiving element receiving a reflected light in scanning once is varied according to scattering of a rotating speed of a polygon mirror, etc., of respective apparatuses, but it is troublesome that manufactures adjust individual apparatuses, and they cannot cope with fluctuations after shipment.
Further, in the conventional methods, in the case where two or more indicators exist on a scanning surface, there arises a problem that their positions cannot be detected accurately.
One object of the present invention is to provide an optical scanning-type touch panel or an optical scanning-type input device which is capable of detecting a position of an indicator for indicating on a plane specified as an object to be touched (hereinafter called as coordinate surface in short) accurately by judging a size of the indicator.
Another object of the present invention is to provide an optical scanning-type touch panel in which when the position is indicated by a finger or pen, if a hand or elbow touches a display screen, its detected position is made to be invalid, an accurate position indicated by the finger or pen can be detected.
Still another object of the present invention is to provide an optical scanning-type touch panel in which scanning lights by an optical scanning element can be prevented from being cut off by a light emitting element, a light receiving element or the like by arranging the light receiving element and light scanning element farther from the edge sides of a rectangular coordinate surface than the light emitting element, and a sufficient scanning angle can be obtained.
Still another object of the present invention is to provide an optical scanning-type touch panel in which a light emitting element for emitting a scanning light is arranged so that an optic axis of the emitted light intersects a scanning surface and a light receiving element for receiving reflected scanning light is arranged so that directivity of the received light intersects the scanning surface, and thus a light send/receive part can be miniaturized and further the whole of the apparatus can be miniaturized.
Still another object of the present invention is to provide an optical scanning-type touch panel in which a defect of faults of an optical isolator in the case of using a half mirror is eliminated.
Still another object of the present invention is to provide an optical scanning-type touch panel in which an influence of a change in sensitivity due to a change in temperature of light receiving element is eliminated so that accurate measurement can be made.
Still another object of the present invention is to provide an optical scanning-type touch panel which is capable of automatically correcting scattering of the time when a light receiving element receives a reflected light at scanning once in respective apparatuses, and capable of coping with change after shipment easily.
Still another object of the present invention is to provide an optical scanning-type touch panel in which when two or more indicators exist on a scanning surface, a state that their accurate positions cannot be detected is frequently temporary, so in this case the positions are not detected so that useless confusion can be avoided.
An optical scanning-type touch panel of the present invention is provided with a light recurrence reflection member in at least three sides of a rectangular coordinate surface, at least two light send/receive members having a light scanning element for angularly scanning a light in plane which is substantially parallel with the coordinate surface and having a light receiving element for detecting the light from the light scanning element which is reflected from the light recurrence reflection member on the outside of the coordinate surface, and the optical scanning-type touch panel detects existence of an indicator and a scanning angle based on a received light amount detected by the light receiving element, and measures a cut-off region where light scanning is cut off by the indicator according to the detected result, and calculates a position of the indicator, namely, an indicated position.
Here, when an angular velocity of the scanning light is constant, information of the scanning angle can be obtained from information of the scanning time. Moreover, a cross-section length of the indicator can be calculated based on the measured cut-off region and the calculated indicated position, and information about a size of the indicator can be obtained according to the calculated cross-section length. As mentioned above, in the present invention, information about the position and size of the indicator is obtained.
Information about sizes of various objects which are supposed to touch the coordinate surface is stored previously, and information about the actually obtained size of the indicator is compared with the stored information about sizes so that a type of the current indicator is judged according to the compared result. A judgment is made as to whether or not the indicator is an indicator for actually specifying a position, and only when the indicator is an indicator for specifying a position, the result of measuring the cut-off region and the result of calculating the indicated position are effective. Therefore, false detection of an indicated position by a wrong indicator can be prevented, and thus an indicated position by a correct indicator can be always detected.
When two more light receiving elements for receiving a light from the light emitting element which is reflected from the light recurrence reflection member are arranged in each light send/receive member so as to be close to both the end portions of the detecting region of the coordinate surface, the light receiving signals of the light receiving elements can be used as scanning start/end timing signals.
When two more light reflecting elements for reflecting a light from the light emitting element and making the light be incident to the light receiving element are arranged in each light send/receive member so as to be close to both the end portions of the detecting region of the coordinate surface, the light receiving signals of reflected light from the light reflecting elements can be used as scanning start/end timing signals.
When a region where the indicator cannot enter is provided between the coordinate surface and the light recurrence reflection member, even if the indicator is in any position on the coordinate surface, the scanning start/end timing can be obtained securely, and an indicated position can be detected accurately.
Further, the scanning light from the light emitting element is a pulse light, and pulse light emission is controlled. For example, a pulse light is of sufficiently short period, a number of pulses can be cope with a scanning angle in the ratio of 1:1. Moreover, when the emission time for once is shortened, or the emission strength for once is weakened, or the light emitting period is lengthened, average radiant energy from the light emitting element can be reduced. Further, when the scanning start timing in each optical scanning is varied, even if the light emitting period becomes long, the detection of the indicator is not omitted.
In addition, the arrangement of the light emitting element and light receiving element is considered so that the scanning light from the light scanning element is not cut down by components accompanying the light emitting element and light receiving element. Therefore, the optical scanning by the light scanning element is sufficiently scanned in the direction of the scanning region, and thus a sufficient scanning angle can be obtained.
Furthermore, the light emitting element is arranged so that the light emitting direction of the light emitting element intersects the scanning surface of the light scanning element, and the light receiving element is arranged so that the directivity of light receiving by the light receiving element intersects the scanning surface of the light scanning element. As mentioned above, since the arrangement of the light emitting element and light receiving element is considered, the light send/receive member can be miniaturized and accordingly the whole apparatus can be miniaturized.
In addition, the light send/receive member further includes a light separating element for passing the light emitted from the light emitting element towards the light scanning element and separating the reflected light from the light recurrence reflection member to the light receiving element, and the light separating element includes a reflector having a reflecting surface for reflecting the reflected light from the light recurrence reflection member in the direction of the light receiving element and having an opening which is bored between the reflecting surface for passing the light emitted from the light emitting element towards the light scanning element and the back surface of the reflecting surface. The light which is allowed to pass from the light emitting element towards the light scanning element is controlled by this opening.
In the above constitution, the reflector is constituted so that its reflecting surface and back surface are not parallel with each other. As a result, a percentage of the light emitted from the light emitting element being received directly by the light receiving element becomes low.
In the above constitution, a reflecting mirror whose reflecting surface intersects the coordinate surface is further provided, and the light scanning element scans the light emitted from the light emitting element in a plane which intersects the coordinate surface, and the reflecting mirror reflects the light scanned in the plane where the light scanning element intersects the coordinate surface in a plane parallel with the coordinate surface. The light emitted from the light emitting element is scanned by the light scanning element in the plane intersecting the coordinate surface and the light scanned by the light scanning element in the plane intersecting the coordinate surface is reflected by the reflecting mirror in the plane parallel with the display screen, so the constitution of the apparatus can be miniaturized. At this time, when the reflecting surface of the reflecting mirror is set so as to intersect the coordinate surface at 45xc2x0, the light emitted from the light emitting element is scanned by the light scanning element in the plane intersecting perpendicularly to the coordinate surface, and thus the constitution of the apparatus can be further miniaturized.
Another optical scanning-type touch panel of the present invention includes a light recurrence reflection member, at least two light send/receive members, a comparator for comparing a receiving signal by the light receiving element with a predetermined threshold value and in the case where an indicator exists in a coordinate surface, detecting timing of shielding due to the indicator, a measuring unit for measuring a cut-off region of a scanning light due to the indicator in the coordinate surface based on a scanning angle in the optical scanning element and a compared result of the comparator, a calculating unit for calculating a position and size of the indicator in the coordinate surface according to the measured result by the measuring unit, a signal level detector for detecting a lowest level of a light receiving signal of the light receiving element, an adder for adding a predetermined value to the level of the signal detected by the signal level detector, and a threshold value setting unit for setting the addition value obtained by the adder as a threshold value to the comparator. Since the lowest level of the light receiving signal of the light receiving element is detected and the value obtained by adding the predetermined value to the detected signal level is set to the comparator as a threshold value, an influence of a change in a level of the light receiving signal due to a change, etc. in the sensitivity is not given.
In the above-mentioned constitution, the signal level detector detects the lowest level of the light receiving signal of the light receiving element and a lowest level of the light receiving signal in the case where the light receiving element receives a scanning light with the indicator not existing on the coordinate surface, and the adder adds a value between the two levels detected by the signal level detector to the lowest level of the light receiving signal of the light receiving element. Therefore, a threshold value of the comparator is set to a suitable value.
Still another optical scanning-type touch panel of the present invention includes the light recurrence reflection member, at least two light send/receive members, comparator, measuring unit and calculating unit, and time counter for counting a continuous time of a level of the light receiving signal of the light receiving element in the case where the indicator does not exist on the coordinate surface. The measuring unit performs measurement in the case where the compared result of the comparator is changed within a time counted by the time counter. Since the continuous time of the level of the output signal of the light receiving element in the case where the indicator does not exist on the coordinate surface is counted, and the measurement is performed in the case where the compared result of the comparator is changed within the counted time, it is not necessary to adjust respective apparatuses.
In the above-mentioned constitution, the time counting by the time counter is performed automatically at the time of actuation or in the case where a predetermined instruction is given. Since the time counting by the time counter is performed automatically at the time of actuation or in the case where the predetermined instruction is given, scattering of the time at which the light receiving element receives a reflected light in scanning for once in the respective apparatuses is corrected automatically.
Still another optical scanning-type touch panel of the present invention includes the light recurrence reflection member, at least two light send/receive members, comparator, measuring unit and calculating unit, and counter for counting a number of times cut-off every time when the comparator detects a cut-off timing due to the indicator existing on the coordinate surface. The measuring unit does not perform measurement in the case where a counted value of the counter is two or more. In the case where the comparator detects a cut-off timing due to the indicator existing on the coordinate surface twice or more, the measurement is not performed by the measuring unit, so a situation that detection becomes impossible and thus useless confusion occurs can be avoided previously.
In the aforementioned optical scanning-type touch panel of the present invention, when the optical scanning element is composed of a polygon mirror having three through six reflecting surfaces, the polygon mirror composing the optical scanning element can be constituted small.
In the present invention, xe2x80x9ctouchxe2x80x9d represents only the case where the indicator is in contact with the coordinate surface, but xe2x80x9ctouchxe2x80x9d includes the case where the indicator is not in contact with the coordinate surface (non-contact touch). In other words, the present invention can be applied to the state where the indicator is positioned above the coordinate surface, not coming in contact with it.
The above and further objects and features of the invention will more fully be apparent from the following detailed description with accompanying drawings.